Pattern is not matching when it contains a new line

Question

Here is my code

 Pattern pbold = Pattern.compile(".*\\* *(.*?) *\\*.*");
 Matcher mbold = pbold.matcher(s);
 mbold.find();

Please give an example of the input that you are trying to match. — Andy Turner, May 23 '16 at 07:24
"*apple*" work with out new line but when take new line not working then — Ayush, May 23 '16 at 07:25
That regex will not match `apple`, with or without a newline. — Andy Turner, May 23 '16 at 07:26
Also look at the DOTALL option `(?s)`, so `.` matches newline characters as well. — Andrew Williamson, May 23 '16 at 07:26
@Andy Turner exactly , without new line it find out otherwise not — Ayush, May 23 '16 at 07:29

score 1 · Answer 1 · edited May 23 '17 at 12:31

1

What you need is the metacharacter that matches whitespaces charaters: (?s) This whitespace metacharacter matches:

A space character
A tab character
A carriage return character
A new line character
A vertical tab character

For more info about this special characters, please consult The Java Tutorials - Regular Expressions - Predefined Character Classes.

The code belows matches the case you need:

String s = "abc021\n" +
            "34-+\n" +
            "*\n" +
            "a\n" +
            "p\n" +
            "p\n" +
            "l\n" +
            "e\n" +
            "*\n" +
            "fga32\n" +
            "49";
    Pattern pbold = Pattern.compile(".*\\* *((?s).*?) *\\*.*");
    Matcher mbold = pbold.matcher(s);
    mbold.find();

There is also a similar question here: Regular expression does not match newline obtained from Formatter object

edited May 23 '17 at 12:31

Community

1
1

answered May 23 '16 at 07:51

Esteban

74
4

I want `*apple*` will be became *apple* in bold without stars . – Ayush May 23 '16 at 10:05
Thanks for your feedback @AyushSaxena. The regex above matches words between stars even across lines. I need precise description on your **input** and **expected output** to give you better feedback. – Esteban May 23 '16 at 10:27
no consequtive ** will be replace I have done this Pattern pbold = Pattern.compile(".*\\* *(.*?) *\\*.*"); – Ayush May 23 '16 at 10:43
but this replace ** also to bold ** = nothing hope you understand – Ayush May 23 '16 at 10:44
If I understood correctly: INPUT: `I want *apple* and **orange** in bold` OUTPUT: I want **apple** and **orange** in bold The problem is **Java regex does NOT support recursive patterns**; i.e. it's not possible to recognize something like `**apple**` with a variable number of stars (e.g. `***apple***`). My suggestion to simplify this regex is to match the innermost pair of stars. For example: INPUT: `I want *apple* and **orange** in bold` OUTPUT: I want **apple** and * **orange** * in bold – Esteban May 23 '16 at 11:58
Another possibility is to extend the code that matches words/phrases to be set in bold, to match multiple stars. But unfortunately you have to do it manually. An also consider the following case: INPUT: `*apple* and **orange** match *fruit**` OUTPUT: **apple** and **orange** match **fruit** * – Esteban May 23 '16 at 12:03
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/112681/discussion-between-esteban-and-ayush-saxena). – Esteban May 23 '16 at 12:07

score 0 · Answer 2 · answered May 23 '16 at 07:51

0

Use flags igm like below:

Pattern pbold = Pattern.compile(".*\\* *(.*?) *\\*.*");
 Matcher mbold = pbold.matcher(s, Pattern.MULTILINE|Pattern.CASE_INSENSITIVE|Pattern.DOTALL);
 mbold.find();

answered May 23 '16 at 07:51

nikli

2,281
2
24
38

1

`Pattern.MULTILINE|Pattern.CASE_INSENSITIVE` are completely redundant here. None of the tokens used in the regex is affected by these 2 flags. – nhahtdh May 23 '16 at 09:09

score 0 · Answer 3 · answered May 23 '16 at 08:08

This regular expression might solve your problem...

 Pattern pbold = Pattern.compile(".*\\*[ \n]*(.*?)[ \n]*\\*.*");
 Matcher mbold = pbold.matcher(s);
 mbold.find();

If this doesn't solve it..please elaborate what you are trying to get through this expression.

Pattern is not matching when it contains a new line

3 Answers3